Birth Control and Future Fertility
A question I often get asked is “does the birth control hurt your fertility?” The reality is birth control is a very all encompassing category. It's contraception.
Often when people say birth control, they're talking about the pill or the combined estrogen and progesterone contraceptive pill. The birth control pill does not cause infertility. It is ethinyl estradiol with a different type of progestin. The doses of ethinyl estradiol can vary. A pill that's a tricyclic has different levels every week. A pill that is monophasic, which is what most of us use now, is going to be the same estrogen throughout the entirety of the pill pack. A low pill, or a low low, has lower levels of estrogen, which generally people like to be on the lowest level you need to prevent ovulation. However, the lower the estrogen goes, the more likely you might be to have breakthrough bleeding or spotting. So if that's an issue, you might need to up it to a more regular level. The pill is very short acting, meaning you can miss a single pill and ovulate. FSH can surge, and you can grow an egg, and you can ovulate. We've probably all heard stories about somebody getting pregnant on the pill. It is so short acting that when you're done with it, you're gonna resume to whatever your normal is. One of the issues is that people can be on long term contraceptive, and they take the pill for years and years. Taking the birth control pill for 10 years decreases your chance of ovarian cancer like 90% because the ovary is not going through that ovulation and healing process over and over again. However, when the ovary is in that quiet state for so long, it also gets bored and forgets how to act. So that might mean it's not going to ovulate quite as quickly coming right off the pill because it has to wake up. We know this with ovarian reserve.
What is ovarian reserve?
Also, if you've heard me talk about ovarian reserve, I like to think about the number of eggs that you have as you're born with, all the eggs you're ever going to have, and imagine they're in a vault inside your ovary. Every single month from when you're a baby inside your mother's womb, a group of eggs is released until you start puberty. When puberty starts your body starts making FSH. FSH is follicle stimulating hormone, and each egg grows in a follicle. So now FSH is going to stimulate an egg to grow and you're going to ovulate, and once you ovulate, you're going to have a period, but you are running out of eggs this whole time. We would love a way to really know how many eggs you have and how fast you're losing them. So we could predict the rate of decline of your egg count, but we don't have that. What we know is that as the vault gets more empty, fewer eggs are released every month. So we can do an antral follicle count, which is an ultrasound determination of how many eggs you have. The lower you have, the fewer eggs you have remaining. We can also do a blood test, which is markedly easier than a transvaginal ultrasound. The blood test is AMH, anti mullerian hormone. AMH is made from the granulosa cells, or cells that surround all of the follicles.
Testing Ovarian Reserve After Using Contraception
When your ovaries been quiet for a really long time, those cells start to become less active as well. We know this because on the oral contraceptive pill, you can have a decrease of your AMH, and it's not a real drop. You didn't really lose eggs. You're just not seeing them because they're not as active. The same thing with your ovary has been quiet for so long. It's forgotten how to respond and ovulate. If you try to go into egg freezing after being on continuous birth control pills for 10 years, you might get a lower response than if you took a pill break. The number of eggs you get is correlated with outcomes that could impact your fertility in some way.
Your Period Pattern After The Pill
So the thing to know here is that one, whatever your period pattern is, if you have underlying PCOS, if you have underlying endometriosis, that irregularity or that pain will come back when you stop the pill. I tell people that it should take around three months to get your regular period back. If you don't, you should go get an evaluation to see what is going on. Another thing, especially if you use a low estrogen pill, and you take it all the time like you never have a period, which I'm fine with. I took it like that for many years because you don't need a period if you're on contraception. When you are doing that, you are thinning out the uterine lining, and that's why you're not having a period, which is also fine. When you want to come off of it and get pregnant, your body hasn't built a uterine lining in a long time, and that can take a while. If you're approaching the period where you want to get pregnant soon, but you've been on the birth control pill, and you take it continuous, so you don't ever have a period, you should start taking those five day pill breaks. This way you get a period again, and you start bleeding every month because that's going to be a sign that that lining is growing back and getting thicker. That is something that sometimes in patients, I even have to give them extra estrogen and prime that lining if we're trying to get back to a thicker lining or an implantation sooner. As far as the birth control pill causing you to run out of eggs, to not ovulate afterwards, go into PCOS or develop some type of anovulation from the pill, that is not true. When you stop the pill, whatever your normal is has to come to surface. So start tracking, and if things are irregular after three months or you have no period, I saw a patient who hadn't had a period in a year after stopping the pill. That's too long, and something's going on. You could have hypothalamic amenorrhea, PCOS, thyroid disease, or high prolactin. There's a bunch of different things. Go get an evaluation.
Other types of contraception
Plan B does not cause infertility or long term fertility issues, or issues with your egg count. The Depo Provera shot is my least favorite of all the contraceptives. Depo provera is an injectable progesterone. You might think of it as “the shot.” You can take it and not worry for three months. So it is proven in studies in almost everybody to prevent ovulation for three months. So if you're using it for contraception because you don't want to be pregnant, you need to take that shot every three months. If you suddenly want to be pregnant, the effect of depo provera could actually last for 18 months in some people, meaning that progesterone can prevent you from ovulating for 18 months. If you think you're going to get pregnant in the next two years, depo is not a good choice for you. A progesterone based IUD is a fantastic long term contraceptive option, but many of them do thin the uterine lining significantly. Please get it removed three to six months before you want to get pregnant because the uterine lining does take time to build back up. Those are some of the basics about contraception and what you need to know about its impact on your fertility.
